State of Technology Report for Force Main Rehabilitation, Final ...

Technology/Method Sliplining/HDD/Pipe Bursting/Direct Bury
Temperature Range,
o F
Limited to 140 o F and below. Above 73 o F standard internal pressure de-rating
factors apply for long-term elevated temperature exposure
Renewal Length, feet Standard guidance of 300-500 feet for pipe bursting with length of >1,000 feet
completed in a single burst. Slipline length of 3,500 feet in a single pull have
been completed. HDD lengths of over 5,100 feet in a single length.
Other Notes Not available.
III. Technology Design, Installation, and QA/QC Information
Product Standards AWWA C900, AWWA C905, NSF 61 Certified (for potable water applications),
ASTM D2241, D3034, F679, D1785
Design Standards AWWA C900, AWWA C905
Design Life Range 100+ years
Installation Standards ASCE “Pipe Bursting Projects” - ASCE Manual and Report on Engineering
Installation
Methodology
Practice #112. AWWA installation standard is in development.
For sliplining, host pipe is cleaned and CCTV inspected. Depending on site
logistics, the Fusible PVC pipes can be strung out and the joints butt fused
above grade prior to insertion, or butt fused in the ditch. For pipe bursting, the
pipe normally is butt fused in a single length. Static burst methods only are used.
The fused PVC pipe is either winched into the host pipe for sliplining, or pulled in
behind the expansion head for pipe bursting. A non-rigid connection from the
pipe to the expansion head is used. In all installation methods the maximum
recommended pull force and the minimum recommended bend radius must be
followed.
QA/QC The stock pipe is subjected to all of the normal QC requirements in AWWA
C900/C905, including dimensional conformance, flattening, acetone immersion,
hydrostatic, and burst tests. UGSI includes impact, heat reversion, and axial
tensile testing as well. In addition 3 rd party labs are used to confirm extrusion
results on key tests prior to shipment. The fusion process parameters of pressure
and the time are recorded for each joint using a datalogger. Additional parameters
such as the heat plate temperature are also recorded.
IV. Operation and Maintenance Requirements
O&M Needs No special O&M needs.
Repair Requirements
for Rehabilitated
Sections
Cut out and replace with AWWA PVC of the same OD, using repair clamps and
all standard PVC and DI water works fittings.
V. Costs
Key Cost Factors Benefits: Due to the high tensile strength of PVC (compared to softer
thermoplastic rehab materials), Fusible PVC allows longer lengths of cased and
uncased pulls, which can reduce the number and cost of pit excavations required.
Reduced wall thickness for a given pressure maximizes inner diameter (ID) for a
given outer diameter (OD) either maximizing flow in an OD constrained
environment or minimizing cost of pipe material and installation as well as risk
for a given ID and pressure requirement. Additional ease and reduced cost of
reconnections using standard water works fittings.
Limitations: Due to limitations of bending radius, Fusible PVC may require
longer insertion pits over softer thermoplastics.
Case Study Costs Fusible PVC pipe was used for a 5,120 feet directional drill crossing under the
Beaufort River for the Beaufort Jasper Water & Sewer Authority in June of 2007
and was compared in costs to both steel and HDPE pipe. The overall project cost
$1.7 million and the customer estimated savings of $400,000 (materials and
installation) by selecting Fusible PVC pipe over other materials for the drill
portion.
VI. Data Sources
References www.undergroundsolutions.com
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